The Defense Department has spent close to $3 billion since 2007 to treat and study traumatic brain injuries and post traumatic stress disorder — the leading injuries suffered by U.S. military personnel in Iraq and Afghanistan. But a federal investigation finds that the department's programs are so disorganized that it's difficult to figure out how the money has been spent.

The report by the Government Accountability Office says that nobody in the Defense Department coordinates all the programs on brain injuries and PTSD. It finds that by law the Defense Department is required to keep track of who has spent what, and on what kinds of treatments and studies. But auditors checking the figures have discovered the numbers are "unreliable."

The GAO says it has been telling the Defense Department for years now that some of the programs on brain injuries and PTSD are disorganized and hard to track. Officials at the Defense Department responded that they've been working on doing better.